Flexible closure and plunger for cartridge-container



J 21,1960 H. J. H. SCHMIDT ETAL 2,941,699

FLEXIBLE CLOSURE AND PLUNGER FOR CARTRIDGE-CONTAINER 2 Sheets-Sheet 1 Filed April 8, 1957 INVENTOR. HAROLD J. H. SCHMIDT VINCENT G. BIEDENSTEIN BY 2 o E a I ATTORNEY June 21, 1960 H. J. H. SCHMIDT ETAL 2,941,699

FLEXIBLE CLOSURE AND PLUNGER FOR CARTRIDGE-CONTAINER Filed April 8, 1957 2 Sheets-Sheet 2 FIG.6.

/o INVENTOR.

HAROLD J. H. SCHMIDT VINCENT G. BIEDENSTEIN BY z 9 i a ATTORNEY United tates Patent Mo., acorporation-ofMissoun 7 Filed A r. 8, 1957,, SEX-1ND. 65.1;464

'2 Claims. (Cl. ZZZ- 32.7)

This invention relates to .an end closure for sealing one end of a disposable type of cartridgecontainer used in dispensing guns for grease, oil, caulking compounds, and the like. More specifically, the invention relates :to an end closure for a cartridge tube which .is an efiective seal against the leakage of oil, solvents, and the like, in the material constituting the charge for the cartridge, whatever that may be, which enclosure is frangible under pressure of the ram of the dispensing gun to form a pisston or plunger operating to force the material out of the opposite end of the cartridge. In this respect, the disclosure and the construction herein is similar to and operates identically with that. shown in a prior application to Vincent G. Biedenstein, Serial 'No. 620,887 filed November 7, 1956-, for Slip Cover and Plunger for Cartridge-Container.

The distinguishing feature here relates to both the material itself and the manner of construction of the end closure. As stated in the co-pending application of Vincent G. Biedenstein, Serial No. 648,388, filed March 25, 1957, for Caulking Cartridge, Spout Type, End Closure (Docket No. RC-3-G), prior cartridges have had the disadvantage that the discharge of material would continue from the spout after ram pressure of the dispensing gun had ceased. This continued discharge means either a loss of time or a loss of material to the operator. The prior Biedenstein application discloses one manner of constructing a dispensing spout for the cartridge-container, which can be applied to any cartridge for use in any type of gun for solving this problem. The instant invention can be applied to any end closure for a cartridge-container to be used in any type of a gun. It operates on the same principle as the improved spout in the prior application to solve the same problem.

According to the present invention, the end closure is in the form of a slip cover placed upon the end of the container tube, upon which it is frictionally retained due to the gripping effect between opposite inside surfaces of a reversible flange on the end closure and the outside and inside surfaces of the tube body of the container. Preferably, the material for construction is a very tough form of polyethylene plastic which is flexible and resilient. The reversible flange is scored at a point to fracture, so that a piston is formed for forcing out the material in the cartridge. This piston is crowned so that when pressure of the plunger of the dispensing gun is applied and released, it will flex inwardly and outwardly, much like the bottom of an oil can. This characteristic provides a better fitting piston and an expansible chamber to eliminate continued discharge from the cartridge spout once the pressure of the plunger is released.

The accompanying drawings illustrate a form of construction embodying the invention, in which:

Fig. 1 is a perspective view of the upper end of a can showing the slip cover in a position to be mounted thereon.

Fig. 2 is a transverse vertical section of a slip cover.

2 Fig. 3 shows the cartridge positioned within acaulking gun ready for use.

Figs. 4, 5 and 6 are operational views showingthe action of :theplunger of the caulking gun as it first engages :the .cover to fracture the cover and form the piston, .as .in Fig. 5, .and :theaction of the piston when the pressure of the plunger .is relieved, as in Fig. 6.

.As shown in Fig. l, the cartridge-container has a body .10 formed .of two or more .plies of spirally wound paper 11 and :12. To one end of this tube of the cartridgecontainer is secured the usual :dispensing spout 14, as shown in :Fig. 3. The instant invention, however, is concerned with sealingthe opposite end of the container can with a suitable cover, which is frangible to form a plunger for-forcing the material sealed-in the container out of'the spout 14. This cover is shown in detail in Figs. land 2, and its operation illustrated inFigs. 4 to 6, inclusive.

:Referring to Fig. 1,'the slip cover, generally indicated as 15, has a central gplunger portion 16 as shownin Fig. 2, which is convex and forms a dome. Surrounding (the central plunger portion 16 is an integrally formed flange 17 with an inner surface .18 thereon dimensioned :so as to tightly fit the internalsurtace of the cartridge 10. On the flange :17 is a rim 1 9' with anouter lip 20 having an :outer surface 21 opposing surface 18, which is dimensioned rto snugly engage the outer surface of the cartridge container body 10.

'Between'the flange 17 and the lip 19 is a groove 23, which forms a score line-upon which fracture takes place, as will "be hereinafter described.

A re-en'trant flangeis formed between surface 18 and the lip 20 which wedgingly engages with the end of the cartridge tube body 10 so as to effectively seal against leakage of solvents and oils during storage. The slip cover 15 is preferably formed of plastic material such as polystyrene, which has the characteristics of flexibility and resilience, as well as toughness. It can be secured in place on the end of the cartridge container 10 by any suitable solvent or adhesive.

Fig. 4 shows the slip cover assembled with the container tube 10 and illustrates the tight sealing action between the flange and lip and the cartridge-container body 10. The slip cover shown here, and so far described, is very similar in construction and operation to that shown in a co-pending application of Vincent G. Biedenstein, Serial No. 620,887, filed November 7, 1956, for Slip Cover and Plunger for Cartridge-Container. It differs in that the plunger is convex, and the distinction between these two inventions resides in this feature and its opera tion to obtain the desired results above described.

Operation Figs. 3 through 6 illustrate the operation of this invention. Fig. 3 shows a caulking gun structure having a body 30 which is an open cylinder having mounted thereon a handle 31 for operating the caulking gun by moving the gun plunger 32 to apply pressure to the slip cover of the cartridge-container. The opposite end of the cartridge-container is inserted in the caulking gun 30 so that the spout 14 protrudes, all as illustrated in Fig. 3.

During operation of the caulking gun, the actuation of the jacking mechanism forces the plunger 32', as shown in Fig. 4, against the central portion of the slip cover plunger 16. As this force increases, the plunger 16 tends to flatten under the pressure of the ram 32 causing the flange 18 to expand and form, a very tight fit within the body 10 of the cartridge-container. The expansion is caused by radial forces which are outwardly directed forces transmitted from the dome to the flange. The force of the ram 32 fractures the slip cover at the able, the ram pressure is released by operation of the gun mechanism, which allows the plunger portion to retract and portion 16 of the slip cover to resume its initial shape to relieve the residual pressure present within the cartridge and discontinue the discharge from the spout 14, all in a manner described in a prior applicationof Vincent G. Biedenstein for Caulking Cartridge, Spout Type, End Closure, above mentioned.

In all other respects, the construction described in detail here is substantially identical with the disclosure of the prior first-mentioned application of Biedenstein.

A construction has been described which will form an ideal seal and plunger for a cartridge for a caulking gun, but it is contemplated that obvious modifications of this invention will occur to those skilled in the art which come Within the scope of the appended claims.

We claim:

1. An end closure for one end of a cylindrical disposable cartridge for dispensing viscous materials having a separate cap to act as a piston to discharge these materials from the opposite end of the cylindrical cartridge by direct pressure applied to move the cap through the cartridge, said cap comprising a body portion and a cylindrical flexible, resilient peripheral portion extending around said body portion to act as a seal during the piston action, said body portion being in the form of a flexible domed plunger portion within said peripheral portion having its convex side outwardly and interconnected with said peripheral portion to cause said peripheral portion to expand and form a tight slidable seal internally of the cartridge when said domed plunger is flexed inwardly by direct pressure applied to cause the plunger to slide in the cartridge, said dome being stiff enough to transmit radial expansive forces on said flexible peripheral portion.

2. A disposable type of dispensing cartridge for viscous materials adapted to be operated by a dispensing gun, said cartridge having a cylindrical body for containing the viscous material, a dispensing opening at one end of said body, and a closure cap for the opposite end adapted to move axially through the cylindrical body of the dispensing cartridge to force out the viscous contents when said cap is moved to impose pressure on said contents by an external force applied directly to the outside of said cap, said cap comprising a body portion and a peripheral portion extending around and integral with said body portion dimensioned to slide in said cylindrical body, and said body portion being in the form of an outer flexible domed plunger portion within'said peripheral portion formed of a tough resilient material capable of independently resuming its original domed shape when, axially d'istonted or flattened by adispensing force applied to the outer dome side of said cap to slide it Within said body, whereby said domed cap will flex back to its convex form regardless of internal pressures within the cartridge body and by so flexing tend to Withdraw the contents not dispensed back into the cartridge.

References Cited in the file of this patent UNITED STATES PATENTS 

